Pressure-controlled device



Sept. 18, 1928. I 1,684,530 v F. J. BAST PRESSURE CONTROLLED DEVICE Filed Oct. 1925 2 Sheets-Sheet 1 INVENTOR f/Pfl/V/f J 5/757 A TTOR/VErs WITNESS g Sept. 18, 1928.

F. J. BAsT PRESSURE CONTROLLED DEVICE Filed Oct. 1925 2 Sheets-Sheet 2 A TTOR/VEYS Patented Sept. 18, 1928.

1,684,530 PATENT OFFICE.

FRANK J. BAST, OF NEW YORK, N. 'Y., ASSIG-NOR 'IO CHARLES J". TAGLIABUE MFG. (10., OF BROOKLYN, NEW YORK, A. CORPORATION OF NEW YORK.

PRESSURE-CONTROLLED DEVICE.

Application filed October 6, 1925. Serial No. 60,930.

My invention relates to devices in which operative steps are brought about by pressure and has to do more particularly with devices of this character which are adapted to operate electric switches, valves and other instrumentalities; the invention contemplates a device of simple construction whereby'sudden and abrupt operative movements are developed in an efiicient and reliable manner by the application of pressure extraneously upon said device. Other more specific objects will appear from the description hereinafter and the features of novelty will be pointed out in the claims.

In the accompanying drawings, which show examples of the invention and a specimen installation thereof without defining its limits, Figs. 1 and 2 are sectional elevations of the device in two different forms; Fig. 3 is an elevation showing another form of the device; Fig. 4 is a sectional View on the line 4.4= of Fig. 3 and Fig. 5 is a diagrammatic elevation showing the device, in one of its forms embodied in a temperature controlled valve.

In order to disclose a practical embodiment of the invention and a field for which it is particularly adapted I have shown said invention in the form of a device for making and breaking electric circuits, it being understood that this is for illustrative and descriptive purposes only and that the abrupt operative movements developed in the device may be other than as shown and described and utilized in any case for actuating other instrumentalities or for any other purpose.

In all of its forms the device comprises a member 10 of suitable shape and dimensions and preferably made in the form of a disk of metal possessing the inherent qualities necessary to produce the results hereinafter setforth. The member 10 is generally fiat and at an intermediate point is cupped or dished by being slightly hammered to thin or stretch its structure or otherwise treated to provide the active section 11Qwhich, after being developed. possesses the inherent tendency of abruptly snapping from its normal concave pos tion to an opposed concave position upon the extraneous application of pressure in a predetermined manner. That is to say, the physical characteristics of the member 10 are such that the section 11 or its equivalent will snap into a concave position opposite to that in which it is normally'located, if sufiicient pressure is exerted upon the convex surface of said section; in the preferred arrangement the member 10 is further constructed and arranged so that the section 11, or its equivalent, w ll automatically and instantly return to its initial position as soon as the aforesaid pressure is relieved. The pressure whereby the described actuation of the section 11 from its normal position to an opposed position is effected, may be developed in any suitable manner and by means of any convenient instrumentalities adapted for the purposeat hand; that is to say the aforesaid pressure may be created by means of suitable mechanical elements engaging said section 11, or it may be developed by the action of a suitable compressor or other apparatus, or it may be the result of the expansion and contraction of suitable gaseous or liquid fluids induced by variations in temperature at a given point or place. Furthermore the pressure may be atmospheric pressure made effective upon the convex surface of the section 11 by creating a vacuum upon the concave surface thereof; the terms pressure is thus intended to include any force extraneously applied to the section 11 in a manner to cause it to snap from its normal position to an opposed position. For instance as shown in the drawings the member 10 may be secured upon a casing 12 of suitable dimensions and form, as a cover for the interior of said casing, said interior in such case constituting a pressure chamber 13; the arrangement is such that the active section 11, in its normal position, extends into said pressure chamber 13 with its convex surface a facing into the same as illustrated. The development of the pressure in the chamber 13 may be brought about in any suitable manner in accordance with the purpose and in proper cooperation with such other instrumentalit-ies as may form part of the apparatus in which the device is included or with which it is operativelycombined. In the illustrated example the pressure chamber 13 is accordingly connected by means of an armored or other capillary tube 14, with a thermostatic bulb. 15, the chamber 13, tube. 14 and bulb 15 in such case being wholly or partly filled with a fluid which expands and contracts in response to variations in temperature externally effective upon the bulb 15.

In any case, as pressure in the chamber 13 is developed itwill be extraneously effective upon the section 11 and as soon as said pressure reaches a predctermined point the secltlll tion 11 of the disk will be pressed outwardly and at the proper moment of its adjustment-will snap into a concave position 0pposite to that normally occupied by said section; at this stage said section 11, instead of bulging inwardly accordingly bulges outwardly with respect to the pressure chamber 13 or its equivalent. According to the inherent physical characteristics or" the member 10, the section 11 thereof will either automatically and immediately snap back to its initial position as soon as the pressure in the chamber 13 is reduced or released or said section 11 will remain in its opposed position when the pressure is released, until restored to its normal position by the extraneous application of force in an opposite direction. With the arrangement shown in Fig. 1 of the drawings, the section 11 is designed to snap from its normal position upon the application oi predetermined pressure and to automatically snap back to its normal position when relieved from such pressure; in this example of the invention the pressure in thc chamber13 whereby the section 11 is caused to snap outwardly is developed as a result of increased temperature at the bulb 15 and the aforesaid operations of the disc section 11 are therefore brought about by variations in the temperature which is externally effective upon the bulb 15. Under such conditions the effective movements of the disc section -11, as pressure is extraneously applied thereto and removed therefrom, are abrupt and sudden and thus render the device particularly useful in connection with instrumentalities in which such quick, snappy operative move-' ments are desirable. For instance the device may be used to advantage for automatically making and breaking electric circuits, particularly those in which the currents are of a voltage such as is generally found in light and power circuits for operating heating appliances, lighting means and other apparatus for devices; in such circuits it is essential to effect the make and break quickly so as to prevent arcing and injury to the contact members. As an illustration of such use the disc 10 in Fig. 1 is provided with a stud or other projection 16 located at the central point of the section 11 so as to partake of the operative movements thereof. The stud 16, as shown, is mounted in spaced registry with a movable cont-act member 17 fixed for instance upon a flexible terminal member 18 secured in an auxiliary casing 19 and electrically connected with a binding post 20; the auxiliary casing 19 is combined with the easing 12 in any convenient manner as by means of bolts 21, which as shown in the drawings, may serve also to secure the disk 10 in place, the latter in such casebeing clamped between Opposed annular flanges of the casings 12 and 19: if desired the disk 10 may be soldered,

welded or otherwise permanently fixed upon the casing 12 or its equivalent. A second contact member 17 is carried for instance by a terminal member 18 in operative relation to the contact member 17 within the auxiliary casing 19, the terminal member 18 being suitably mounted within the latter in electrical connection with a binding post 20. The two binding posts 20 and 20 are located upon the exterior'of the auxiliary casing 19 for connecting the device in the electrical circuit of which it forms a part.

With the arrangement shown in Fig. 1 the development of asufiicient pressure in the chamber 13, by a rise in temperature at the bulb 15, will create a force extraneously effective upon the section 11 of the disc 10 to press it outwardly and at the proper moment 01 its adjustment cause said section 11 to snap from the position illustrated in the drawings to an opposite concave position as previously described and as shown by dotted lines in Fig. 1. [is this abrupt changes of the disc 10 from one position to another occurs, the stud 16 or its equivalent will be carried along and because of its engagement with the member 18 will force the contact member 17 into engagement with the contact member 17 and thereby close the electric circuit of which said contact members form a part; the circuit may include an alarm or any device capable 011 being electrically actuated for a predetermined purpose when the circuit is closed. During any initial movement of the disc from its normal posit/on to a point beyond which its inherent characteristics cause said disc to abruptly snap to an opposed position, the stud will move through the space between it and the member 18 without performing any function, and said stud will come into engagement with said member 18 at approxi mately the moment the disc 10 is ready to snap; it will be understood that the spacing of the stud 16 from the member 18 or any equivalent arrangement is calculated to secure this result. Because of this arrangement the contacts 17 and 17 are adjusted relatively to each other by said disc only when the latter snaps from one position to another. In this way any. gradual approach of the contacts toward each other or any gradual separation thereof is avoided and the movements of the contact members relatively to each other are very abrupt. l/Vhen the pressure in the chamber 13 drops, as a result of a decrease in temperature at the bulb 15, the section 11 of the disc 10, because of its inherent characteristics, will immediately snap back of its own accord, preferably without any preliminary movements, to its initial position and shift the stud or its equivalent 16 away from the member 18: as a result of this contact member 17 is disengaged from the contact member 17 and the electric circuit is broken. The effective operative movements of the section 11, from its -normal position and back again, being abrupt and sudden, the

engagement of the-contact members 17 and 17! with, and their disengagement from each other will be correspondingly sudden and abrupt so that arcing and burning-of the coni tact members is, positively avoided, It will when said section snaps back into place as the pressure is relieved without in any way departing from the inventive idea.

In some cases the auxiliary casing 19 may be fluid tight-and contain an inert gas for protecting the contact points against burning; the'arrangement, under such is always such that this gas does not create or develop an opposing pressure upon the disc 10 sulficient to interfere with the invtendedoperatio'ns thereof. 'As shown in Fig.-

2 th e chambers 13 and 19'of-.the casings 13 and 19 respectively may comprise differential pressure chambers connected, "by means-of pipes or the like 22 and 22 with suitable independent sources of pressure. In the latter arrangement the section 11. of the disc 10 is snapped from the position shown in Fig. 2 each time the pressure in the chamber 13 exceeds that in the ghamber 19 to a predetermined extent and, because of its inherent tendency, is returned. to its normal position as soon as the pressures in the two chambers areagain equalized. As the section 11 is thus actuated the stud-16 will be correspondingly operated to either shift the contact members 17 and 17 into engagement with each other or to permit them to become separated to thereby make or break the electric 'circuit. The form ofthe device shown in Fig. 2 further 'illustrates'that arrangement of the invention in which the disc 10 is of such physical characteristics that its section 11, when snapped from the position shown by an extraneous application developed in the chamber 13, to an opposed position, remains in said opposed position regardless 'of any drop in the pressure in said chamber 13". Under such conditions the section 11 would be caused to snap back to its' normal position for instance by the application of a. proper degree of pressure'developed in the chamber 19". ;In other words the section 11 is snapped from one concave position to an opposed'concave position by means of pressure created in the chamber 13'-'and efi'ective in the direction of thearrow b in Fig. 2 and is'snapped from said last ,named position back to its initial position 7 by means of pressure created in 'the chamber 19 and exerted in the direction of the arrow c in'Fig. 2, the pressures'in, such case being conditions,

either manually or automaticallyas may be desired. 1

For the purpose of enabling the snapping instant, at which the section '11 of the. disc 10,

under the influenceof extraneously applied pressure, snaps from its normal concave pos1- t1on to an opposed-concave position, or in other words, the interval between the snap ping in one direction and in the ther direction, to be adjusted, a sprin 23 may be provided within the auxiliary casing 19 with its one end in eng'jagement with the disk 10 approximately in registrwith the peripheral boundary of the section 11 thereof, as shown in Fig. 1. The other end of this spring 23,

-which in the illustrated example is shown, in

the form of a coil spring, engages an adjusting member 24, 'adjustably mounted upon the auxiliary casing 19 for instance, by means of a screw-threaded stem 25; the latter projects outwardly beyond said casing 19 and is pro-. vided with a head 26 to facilitate the actuation of said stem 25 audits member 24. As the stem 25 and member 24 are adjusted relatively to the casing 19, the tension of the spring 23 on-the disc 10 will be correspondingly increased or diminished. "As a result of this, the snapping instant of the section may -.be varied at will to require either a physical character or the spring 23 and of the adjusting meansmay be varied without greater or lesser pressure to bring it about;

affecting the efficiency of the instrumen talities.

Under certain circumstances it may be .desirable, in order to provide a plurality of controls, to utilize a plurality of discs each having a different snapping instant. An example of this type of the device is shown in Figs. 3 and 4 in which the pressure chamber 13 is provided upon opposite sides with Ilu discs 10 and 10 respectively each of. which is constructed and/or arranged to havea differ ent snapping instant. With this arrange ment as the pressure 1n the chamber 13 reaches a certain predetermined point in the disc 10 will be snapped from its normal position to an opposed position, this being foldisc 10 from its normal to an opposed position when thepressure in the chamber 13 reaches a predetermined higher point. As the pressure'is relieved the discs 10? and 10 will either abruptly return to their normal positions upon the release of the pressures therelowed by a corresponding, snapping-of the on or remain in their abnormal positions until restored to their initial positions in the manner previously set forth herein, this de pending upon the physical characteristics of the discs. Any number of discs may be combined to develop successive abrupt operative movements and to provide successive controls at predetermined intervals or the discs ma be utilized to provide controls of. indepen ent or different instrumentalities. For instance, as shown in Figs. 3 and 4, the disc may carry a projection 16 cooperating with and normally spaced from contact members 17 and 17 to open and close one electric circuit and the disc 1O may be provided with a similar projection 16 cooperating with contact members 17 and 17 to open and close another electric circuit. As illustrated the elements so far described may be contained in a casing 19 with which a capillary tube 14* is connected so that it is in open communication with the chamber 13*; a thermostaticbulb is connected with the free-end of the tube 14" in the customary manner. The unit shown in Figs. 3.and 4 may be used to maintain two different temperatures or pressures at different times or at will or to perform equivalent control functions and in such case may include a switch 29 cooperating with contacts 30 and 31 to cut out one circuit or the other at will. with this arrangement the discs 10 and 10" actuated by the pressure developed in the chamber 13 operate independently to perform their controlling functions according to the switch 29; that is to say one disc although it may be caused to snap will perform no controlling function because it is located in an open circuit.

The unit illustrated or its equivalent may be utilized in many additional ways as for instance to control two heating coils for heat-f ing a bath or chamber, in which case three binding posts will be included in the proper electric circuits. Under such conditions the disc 10 may snap when the temperature reaches for instance 200 F. and thereby cut oil one heater while the disclO will snap when the temperature reaches for instance 220 F. and thus cut oif the other heater. Obviously the device in the form shown by way of example in Figs. 3 and 4 may bewith the thermosensitive member 15 which takes the place of the bulb 15, and which is connected by the capillary tube 14* with the capsular springs 29 of the valve apparatus. In the illustrated installation the capsular springs 29 expand and contract in accordance with variations in the temperature which is externally effective upon the member 15 and actuate the valve 30 to according- 1 control the flow of whatever medium passes t rough the valve casing 31. Coincidentally with the expansion of the capsular springs 29 and the consequent shifting of the valve 30 toward its closed position, as a result of an increase in temperature at the member 15*,a corresponding increase in pressure will be developed in the pressure chamber 13 and thus become effective upon the sectionll of the disc 10; in this way the section 11 will be caused to snap abruptly from its normal concave position to an opposed concave position and willthereby bring the contact member '17 into engagement with the contact member 17 a and close the electric circuit in which said contact members are contained, in. the manner previously set forth. This circuit may include an alarm or other device adapted either to issue a warning or to bring about some other appropriate operative step at the instant of snapping of the sectionll or in other words when a predetermined condition of temperature at the member 15 and/or a predetermined position of the valve '30 is reached. As soon as the condition which caused the aforesaid actuation of the section 1:1 is changed, either automatically or as a result of adjustments subsequent to the actuation of the alarm or its equivalent, and the pressure in the chamber 13 is reduced,

the section 11 will instantly and abruptly snap back to its initial position and thereby bring about a separation of the contact members 17 and 17 and a consequent break in the' electric circuit. It will-be noted that, in the installation of Fig. 5, the stud 16, corresponding to the stud 16, is located upon the flexible member 18 which carries the contact member 17 instead of being mounted upon the disc section 11 as in Figs. 1 and 2','the stud 16 being normally spaced from and engaged by the latter as it snaps from one position to another; in some cases the studs 16, 16, 16", and 16 may be entirely-omitted or they may be replaced by other suitable instrumentalities to provide the desired results.

The device provides a pressure operated instrumentality of extreme simplicity and maximum efiiciency for developing abrupt and instantaneous operative movementsas a result of the extraneous application of pressures created by suitable means-for predetermined purposes; the'device is particularly adapted for control by mechanically created pressures, by pressures developed by air compressors or other apparatus and by pressures resulting from the expansion and contracti n of suitable gaseous or liquid fluids induced. y variations in temperature at a given point .or place.

The abrupt and instantaneous operative movements of the device adapt it specially for making and breaking electric circuits in 130 which the current is of a voltage such as is commonly found in light and power circuits and do awaywith the possibility of arcing and injury to the contact points and avoid the necessity for the use of relays or equivalent devices to carry the electric load.

The active device whereby these results are obtained comprises generally a metal plate or member of single thickness buckled at an intermediate point to provide an active section which, when subjected to a suitable pressure extraneously applied in a direction opposite to the normal buckle of the disc or member, will in most cases, after a slight initial movement, suddenly and abruptly snap in an operatively efiective I movement to an opposed concave position and which, upon the relief of such pressure, will abruptly snap back of its own accord, without any preliminary movement, to its initial position because of its inherent characteristlcs or remaln in its abnormal position llIltll caused to snap back to its initial position by pressure applied in an opposite direction to that of the pressure first applied. The metal member may be made of such thickness and shape as to snap in the indicated-manner at any predetermined pressure: as set forth hereinbefore the range of utility of the device may be increased by combining it with an adjusting means whereby the snapping instant is varied at will. Furthermore in some cases a plurality of members or discs 10 of duplicate phys cal characteristics may'be combined in surfacerengagement with each other to vary the snapping instant in accordance with existing requirements.

When the pressure whereby the device is controlled, is created. as a resiilt'of temperature variations, the gaseous fluid or volatile liquid upon which the temperature is efiectivemay be contained directly and alone in the chamber 13 or its equivalent, in which case the capillary tubing and the thermostatic bulb of the illustrated examples may be omitted. L Various changes in the speclfic torms shown and described may be made within the scope ofthe claims without departingfrom the spirit of the invention;

I claim:

1. In a pressure controlled device, the combination of pressure developing means, a} member provided with a deformed active section subject to the developed pressure and adapted to change its position abruptly upon the application of pressure extraneously thereto and to abruptly resume its normal position of its own accord when said pressure is released, and means whereby the'interval between the snapping instant in one direc tion and in the return direction maybe variably adjusted. I

2? In a pressure controlled devlce, the combination of pressure developing means, a

member provided with a depressed section subject to the developed pressure and possessing the inherent characteristics of first -mov1ng gradually and then abruptly snapping from its normal osition to an opposed position upon the app ication of pressure extraneously thereto and of abruptly resuming said normal position without any preliminary movement when sald pressure is released, and means effective upon said memdirection and'in the return direction may be variably adjusted.

3. In a pressure controlled device, the combination of 'a pressure developing. means, a metallic plate having an active section normally flexed in one direction and subjedt to the developed pressure, said section tending to flatten in response to the extraneously applied prwsure and at a predetermined point in said flattening to abruptly'snap in an effective operative movement to an opposed flexed position when said pressure reaches a predetermined point and to abruptly snap back without any preliminary movement to its normal flexed position when said pressure is released, and means effective 'upon said plate in approximate registry with-the peripheral boundary of its active section, whereby the interval between the snap-pinginone direction and in the return direction may be variably adjusted. 1

4. In a pressure controlled device, the combination of pressure developing means, a

metallic member provided with an active section deformed to impart thereto the inhers ent characteristics of developing abrupt snapping movements, said active. section being subject tot-he developed pressure and to an opposed position upon the application of pressure extraneously thereto and-of abruptly snapping back of its own accord-to said normal position when said pressure is released, means located in such CO-OPBIMLIVG relation to said active section as to be operated thereby only when said section snaps from one position to the other, and means effective upon said metallic member in approxisaid -chamber, said section being deformedto impart t'heretotheinherent characteristics of mate registry with the peripheral boundary normally projecting into the same with its surface subject to the developed pressure in abruptly snapping from its normal position to an opposed position upon the application of pressure extraneously thereto and of abruptly snapping back of its own accord to said normal position when said pressure is released, means located in such cooperative relation to said active section as to be actuated thereby only when said section snaps from one position to the other, and means effective upon said plate-like member in approximate registry with the peripheral boundary of its active section, whereby the interval between the snapping in one direct-ion and in the return direction may be variably ad usted.

6. In a pressure controlled device, the combination of a pressure chamber in which pressure is developed, a metallic plate closing sa1d chamber and having a depressed, active section normall projecting into said chamber with its sur ace subject to the pressure developed therein, said section being hammered to impart thereto the inherent characteristics of abruptly snapping from its normally depressed position to an opposed position. upon the application of pressure extraneously thereto and of abruptly snapping back of ts own accord to said normal position when said pressure is released,"means located in such cooperative relation to said active section as to be operated thereby only when said section snaps from one position to another. and means effective upon said plate in approx]- mat/e registry with the peripheral boundary of its depressed, active section, whereby the interval between the snapping in one irection and in the return direction may be variably adjusted.

7. In a pressure controlled device, the combination of a pressure chamber in which pressure is developed, a metallic plate closing said chamber and having an active section normally flexed into said chamber and tending to flatten in response to the application of pressure extraneously thereto and to abruptly snap to an opposed flexed position when said pressure reaches a predetermined point and to abruptly snap back of its own accord to its normal flexed position when said pressure is released, means located in such cooperative relation to said section as to be operated thereby only when said section snaps from one position to the other, and means effective upon said plate in approximate registry with the peripheral boundary of its active section, whereby'the interval between the snapping in one direction and in the return direction may be variably adjusted.

8. In a pressure controlled device, the combination of a pressure developing means, a metallic plate having an active section normally flexed in one direction and subject to the developed pressure, said section tending to flatten in response to the extraneously applied pressure and to abruptly snap to an opposed flexed position when said premure reaches a predetermined point and to abruptly snap back of its own accord to its normal flexed position when said pressure is released, a plurality of electric contact members comprising terminals of an electrical circuit and located in such operative relation to said active section as to be operatively adjusted relatively to each other by said active section only'when it snaps from one position to the other, and means effective upon said late in approximate registry with the perip ieral boundary of its active section, whereby the interval between the snapping in one direction and in the return direction may be variably adjusted.

9. In a pressure controlled device, the combination of a metallic plate normally flexed in one direction and tending to flatten in response to an extraneously applied pressure and to abruptly snap to an opposed flexed position when said pressure reaches apredetermined point, said plate being further adapted to abruptly snap back of its own accord to its normal flexed position when said pressure is released, thermosensitive means operatively combined with said plate for developing the pressure eflective thereon, in accordance with temperature variations, and means whereby the interval between the snapping of said plate in one direction and in the return direction may be variably adjusted.

10. In a pressure controlled device, the combination of a pressure chamber, a metallic plate closing said chamber and normally flexed into said chamber, said plate tending to flatten in response to the pressure extraneously a plied thereto in said chamber and to abrupt y snap to an opposed flexed position when said pressure reaches a predetermined point and to abruptly snap back of its own accord to its normal flexed position when said pressure is released, thermosensitive means connected with said chamber for developing the pressure therein in accordance with temperature variations, and means whereby the interval between the snapping of said plate in one direction and in the return direction may bevariably adjusted.

11. In a pressure controlled device, the combinationof pressure developing means, a member provided with a deformed active section sub ect to the developed pressure and adapted to change its position abruptly upon the application of pressure thereto and to abruptly resume its normal position when said pressure is released, and means effective upon said member in approximate registry with the peripheral boundary of its active section, whereby the interval between the snapping in one direction and in the return direction may he variably adjusted.

12. In a. pressure controlled device, the comblnation of a pressure chamber, a metallic plate closin said chamber and normally flexed into-sai chamber, said plate tending to flatten in response to the pressure in said chamber and to abruptly snap to an opposed 'chamber for developing the pressure therein in accordance with temperature variations, and adjustable means whereby the interval between the snapping instant of said plate from its normal position and its return snap may be adjusted.

13. In a pressure controlled device, the combination of a pressure chamber, a metallic plate closing said chamber and normally flexed into said chamber, said plate tending to flatten in response to the pressure in said chamber and to abrupt-1y snap to an opposed flexed position when said pressure reaches a predetermined point and to abruptly snap back of its own accord to its normal flexed position when said pressure is released, thermo-sensitive means connected with said I chamber for. developing the pressure therein in accordance with temperature variations, an auxiliary chamber superimposed upon said plate and first named chamber, instrumentalities in said auxiliary chamber arranged in the path of movement of said plate so as to be operatively actuated thereby only when it snaps from one position to the other, and means eflective upon saidvplate whereby the "interval between the snapping in one direction and in the return direction may be variabl adjusted. I r I 14. n a pressure controlled device the combination of a ressure chamber, a metallic plate'closing said chamber normally flexed into said chamber, said plate tending to flatten in response to the pressure in said chamber and to abruptly snap to an opposed flexed position when sai pressure reaches a predetermined point and to abruptly snap back of its own accord to its normal flexed position when said pressure is released, thermo-sensitive means connected with said chamber for developing the pressure therein in accordance with temperature variations, an auxiliary chamber superimposed upon said plate and first named chamber, electrical contact members within said auxiliary chamber comprising terminals of an electric circuit, said members being operatively located relatively to said plate so as to be operated thereby only as it snaps from one position to the other, to control said electric circuit, and

means whereby the interval between the initial snap and the return snap of said plate may be variably adjusted.

15. In a pressure controlled device, the combination of a pressure chamber, a metallic plate closing said chamber normally flexed into said chamber, said plate tending to flatten in response to the pressure in said chamber and to abruptly snap to an opposed flexed position when said pressure reaches a redetermined point and to abruptly snap ack of its own accord to its normal flexed position when said pressure 'is released, thermo-sensitive means connected with said chamber for developing the pressure therein in accordance with temperature variations, an auxiliary chamber superimposed upon said plate and first named chamber, instrumentalities in said auxiliary chamber arranged in' the path of movement of said plate so as to be operatively actuated thereby only as it snaps 'from one position to the other, adjusting means within said auxiliary chamber whereby the interval between the snapping instant of said plate from its normal position and its return snap may be adjusted, and means accessible exteriorl of said auxiliary chamber for setting sai adjusting device. 1

16. Ina pressure controlled device, the combination of a pressure chamber, a metallic plate closing said chamber and having an active section normally flexed into said chamber, said section tending to flatten in response to the pressure in said chamber and to abruptly snap to an opposed flexed position when said pressure reaches a predetermined point and to abruptl snap back of its own accord to its norma flexed position when said pressure is released, thermo-sensitive means connected with said chamber for de-* ,velop1ng the pressure therein in accordance with temperature variations, an auxiliary chamber superimposed upon said plate and first named chamber, instrumentalities in said auxiliary chamber arranged in the path of movement of said plate so as to be' opera-- to thereby vary the interval between the snapping instant of said plate from its nor-- mal position and the snapping thereofin the return direction.

In testimony whereof my hand.

FRANK J. BAST.

I'have hereunto set 

